app/main.py

from fastapi import FastAPI, HTTPException, Depends, Request
from fastapi.middleware.cors import CORSMiddleware
from pymongo import MongoClient
from pymongo.errors import ConnectionFailure
import os
import time
from typing import List, Optional
from datetime import datetime, timedelta, timezone
from app.models import BudgetRecommendation, Expense, Budget, CategoryExpense, RecommendationRequest, RecommendationResponse, RecommendationByNameRequest, RecommendationByNameRequest
from app.smart_recommendation import SmartBudgetRecommender

app = FastAPI(title="Smart Budget Recommendation API", version="1.0.0")

# CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# MongoDB connection - Get from environment variable (set as secret in Hugging Face)
MONGODB_URI = os.getenv("MONGODB_URI")
if not MONGODB_URI:
    raise ValueError("MONGODB_URI environment variable is required. Please set it in Hugging Face secrets.")

try:
    client = MongoClient(MONGODB_URI)
    db = client.expense
    # Test connection
    client.admin.command('ping')
    print("Successfully connected to MongoDB")
except ConnectionFailure as e:
    print(f"Failed to connect to MongoDB: {e}")
    raise

# Initialize Smart Budget Recommender
recommender = SmartBudgetRecommender(db)

# IST timezone (UTC+5:30)
IST = timezone(timedelta(hours=5, minutes=30))

def log_api_call(db, name: str, status: str, response_time: float, endpoint: str = None, error: str = None):
    """
    Log API call to MongoDB api_logs collection
    
    Args:
        db: MongoDB database instance
        name: API name (e.g., "smart budget recommendation")
        status: "success" or "fail"
        response_time: Response time in seconds
        endpoint: Optional endpoint path
        error: Optional error message
    """
    try:
        # Get current time in IST
        ist_time = datetime.now(IST)
        # Format: DD-MM-YYYY HH:MM:SS:IST
        timestamp_str = ist_time.strftime("%d-%m-%Y %H:%M:%S:IST")
        
        # Extract user_id from endpoint (e.g., "/recommendations/user123" -> "user123")
        user_id = None
        if endpoint:
            # Extract user_id from path patterns like "/recommendations/{user_id}" or "/category-expenses/{user_id}"
            parts = endpoint.strip("/").split("/")
            if len(parts) >= 2:
                user_id = parts[1]  # Get the user_id part
        
        log_entry = {
            "name": name,
            "status": status,
            "date": timestamp_str,  # Combined date and time in IST
            "response_time": round(response_time, 3),  # Round to 3 decimal places
            "user_id": user_id,
        }
        
        if error:
            log_entry["error"] = error
        
        # Insert into api_logs collection
        db.api_logs.insert_one(log_entry)
    except Exception as e:
        # Don't fail the API call if logging fails
        print(f"Failed to log API call: {e}")

@app.middleware("http")
async def log_requests(request: Request, call_next):
    """Middleware to log API requests and track response time"""
    start_time = time.time()
    
    # Only log specific endpoints
    endpoint = request.url.path
    should_log = endpoint in ["/recommendations", "/category-expenses"] or endpoint.startswith("/recommendations/") or endpoint.startswith("/category-expenses/")
    
    if should_log:
        try:
            response = await call_next(request)
            process_time = time.time() - start_time
            
            # Determine status
            status = "success" if response.status_code < 400 else "fail"
            
            # Log the API call
            log_api_call(
                db=db,
                name="smart budget recommendation",
                status=status,
                response_time=process_time,
                endpoint=endpoint
            )
            
            return response
        except Exception as e:
            process_time = time.time() - start_time
            # Log failure
            log_api_call(
                db=db,
                name="smart budget recommendation",
                status="fail",
                response_time=process_time,
                endpoint=endpoint,
                error=str(e)
            )
            raise
    else:
        # For other endpoints, just pass through
        return await call_next(request)

@app.get("/")
async def root():
    return {"message": "Smart Budget Recommendation API", "status": "running"}

@app.get("/health")
async def health_check():
    try:
        client.admin.command('ping')
        return {"status": "healthy", "database": "connected"}
    except Exception as e:
        return {"status": "unhealthy", "error": str(e)}

@app.post("/expenses", response_model=dict)
async def create_expense(expense: Expense):
    """
    Disabled: this service does not create expenses.

    All expenses should be created by the main WalletSync app and stored
    directly in MongoDB. This API only reads existing data for analytics.
    """
    raise HTTPException(
        status_code=405,
        detail="Creating expenses is disabled. Use the main WalletSync app to add expenses.",
    )

@app.get("/expenses", response_model=List[Expense])
async def get_expenses(user_id: str, limit: int = 100):
    """Get expenses for a user"""
    expenses = list(db.expenses.find({"user_id": user_id}).sort("date", -1).limit(limit))
    for expense in expenses:
        expense["id"] = str(expense["_id"])
        del expense["_id"]
    return expenses

@app.post("/budgets", response_model=dict)
async def create_budget(budget: Budget):
    """
    Disabled: this service does not create budgets.

    All budgets should be created by the main WalletSync app and stored
    directly in MongoDB. This API only reads existing data for analytics.
    """
    raise HTTPException(
        status_code=405,
        detail="Creating budgets is disabled. Use the main WalletSync app to add budgets.",
    )

@app.get("/budgets", response_model=List[Budget])
async def get_budgets(user_id: str):
    """Get budgets for a user"""
    budgets = list(db.budgets.find({"user_id": user_id}))
    for budget in budgets:
        budget["id"] = str(budget["_id"])
        del budget["_id"]
    return budgets

@app.post("/recommendations/check", response_model=RecommendationResponse)
async def check_and_get_recommendations(request: RecommendationRequest, month: Optional[int] = None, year: Optional[int] = None):
    """
    Check if user has previous data for a category and return recommendations if available.
    
    Request body:
    {
        "user_id": "68a834c3f4694b11efedacd2",
        "category_id": "688c80ca990b63f0e945ecf1"
    }
    
    Response:
    - If user has previous data: returns recommendations
    - If user doesn't have previous data: returns message indicating no previous data
    """
    if not month or not year:
        # Default to next month
        next_month = datetime.now().replace(day=1) + timedelta(days=32)
        month = next_month.month
        year = next_month.year
    
    # Check if user has previous data for this category
    has_data = recommender.check_user_has_category_data(request.user_id, request.category_id)
    
    if has_data:
        # User has previous data - but if they provided budget_amount, use it (they want to set a new budget)
        if request.budget_amount and request.budget_amount > 0:
            print(f"✅ User {request.user_id} has previous data for category {request.category_id}, but provided budget_amount {request.budget_amount} - using provided amount")
            recommendations = recommender.get_recommendation_for_category(
                request.user_id, 
                request.category_id, 
                month, 
                year,
                budget_amount=request.budget_amount  # Use user's provided budget_amount
            )
        else:
            print(f"✅ User {request.user_id} has previous data for category {request.category_id} - using historical data")
            recommendations = recommender.get_recommendation_for_category(
                request.user_id, 
                request.category_id, 
                month, 
                year,
                budget_amount=None  # Use historical data if no budget_amount provided
            )
        
        if recommendations:
            return RecommendationResponse(
                has_previous_data=True,
                recommendations=recommendations,
                message=None
            )
        else:
            # User has data but no recommendations generated (edge case)
            return RecommendationResponse(
                has_previous_data=True,
                recommendations=[],
                message="User has previous data but no recommendations could be generated for this category."
            )
    elif request.budget_amount and request.budget_amount > 0:
        # User doesn't have previous data, but provided budget_amount - generate recommendation based on it
        print(f"ℹ️ User {request.user_id} does not have previous data for category {request.category_id} - using provided budget_amount")
        recommendations = recommender.get_recommendation_for_category(
            request.user_id, 
            request.category_id, 
            month, 
            year,
            request.budget_amount
        )
        
        if recommendations:
            return RecommendationResponse(
                has_previous_data=False,
                recommendations=recommendations,
                message="Recommendation generated based on provided budget amount. User does not have previous spending data for this category."
            )
        else:
            return RecommendationResponse(
                has_previous_data=False,
                recommendations=None,
                message="Could not generate recommendations even with provided budget amount."
            )
    else:
        # User doesn't have previous data and no budget_amount provided
        return RecommendationResponse(
            has_previous_data=False,
            recommendations=None,
            message=f"User does not have previous data for category_id: {request.category_id}. Please provide a budget_amount or create a budget/expenses for this category first."
        )

@app.post("/recommendations/by-name", response_model=RecommendationResponse)
async def get_recommendations_by_category_name(request: RecommendationByNameRequest, month: Optional[int] = None, year: Optional[int] = None):
    """
    Get budget recommendations by Head Category name (instead of category_id).
    This is useful for frontend integration where you only have the category name.
    
    Request body:
    {
        "user_id": "6741abd38d30ab5b7176397f",
        "category_name": "Food & Drinks",
        "budget_amount": 350.0  // optional
    }
    
    Supported Head Category names:
    - Food & Drinks
    - Shopping
    - Housing
    - Financial Expenses
    - Communication, PC
    - Vehicle
    - Transportation
    - Life & Entertainment
    - Investments
    - Income
    - Loan Payment
    - Marketing
    
    Response:
    - If user has previous data: returns recommendations based on historical data
    - If user doesn't have previous data but provided budget_amount: returns recommendations based on budget_amount
    - If user doesn't have previous data and no budget_amount: returns message asking for budget_amount
    """
    if not month or not year:
        # Default to next month
        next_month = datetime.now().replace(day=1) + timedelta(days=32)
        month = next_month.month
        year = next_month.year
    
    # Find category_id by name
    category_id = recommender._get_category_id_by_name(request.category_name)
    
    if not category_id:
        return RecommendationResponse(
            has_previous_data=False,
            recommendations=None,
            message=f"Category '{request.category_name}' not found in database. Please check the category name or create the category first."
        )
    
    # Now use the existing check endpoint logic
    has_data = recommender.check_user_has_category_data(request.user_id, category_id)
    
    if has_data:
        # User has previous data - use it for recommendations
        print(f"✅ User {request.user_id} has previous data for category '{request.category_name}' (id: {category_id}) - using historical data")
        recommendations = recommender.get_recommendation_for_category(
            request.user_id, 
            category_id, 
            month, 
            year,
            budget_amount=None  # Don't use budget_amount if user has historical data
        )
        
        if recommendations:
            return RecommendationResponse(
                has_previous_data=True,
                recommendations=recommendations,
                message=None
            )
        else:
            return RecommendationResponse(
                has_previous_data=True,
                recommendations=[],
                message="User has previous data but no recommendations could be generated for this category."
            )
    elif request.budget_amount and request.budget_amount > 0:
        # User doesn't have previous data, but provided budget_amount
        print(f"ℹ️ User {request.user_id} does not have previous data for category '{request.category_name}' (id: {category_id}) - using provided budget_amount")
        recommendations = recommender.get_recommendation_for_category(
            request.user_id, 
            category_id, 
            month, 
            year,
            request.budget_amount
        )
        
        if recommendations:
            return RecommendationResponse(
                has_previous_data=False,
                recommendations=recommendations,
                message="Recommendation generated based on provided budget amount. User does not have previous spending data for this category."
            )
        else:
            return RecommendationResponse(
                has_previous_data=False,
                recommendations=None,
                message="Could not generate recommendations even with provided budget amount."
            )
    else:
        # User doesn't have previous data and no budget_amount provided
        return RecommendationResponse(
            has_previous_data=False,
            recommendations=None,
            message=f"User does not have previous data for category '{request.category_name}'. Please provide a budget_amount to get recommendations."
        )

@app.get("/recommendations/{user_id}", response_model=List[BudgetRecommendation])
async def get_budget_recommendations(user_id: str, month: Optional[int] = None, year: Optional[int] = None):
    """
    Get smart budget recommendations for a user based on past spending behavior.
    
    Example response:
    {
        "category": "Groceries",
        "category_id": "688c80ca990b63f0e945ecf1",
        "average_expense": 3800,
        "recommended_budget": 4000,
        "reason": "Your average monthly grocery expense is Rs.3,800. We suggest setting your budget to Rs.4,000 for next month.",
        "confidence": 0.85,
        "action": "increase"
    }
    """
    if not month or not year:
        # Default to next month
        next_month = datetime.now().replace(day=1) + timedelta(days=32)
        month = next_month.month
        year = next_month.year
    
    recommendations = recommender.get_recommendations(user_id, month, year)
    return recommendations

@app.get("/category-expenses/{user_id}", response_model=List[CategoryExpense])
async def get_category_expenses(user_id: str, months: int = 3):
    """Get average expenses by category for the past N months"""
    category_expenses = recommender.get_category_averages(user_id, months)
    return category_expenses

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)





# from fastapi import FastAPI, HTTPException, Depends
# from fastapi.middleware.cors import CORSMiddleware
# from pymongo import MongoClient
# from pymongo.errors import ConnectionFailure
# import os
# from typing import List, Optional
# from datetime import datetime, timedelta
# from app.models import BudgetRecommendation, Expense, Budget, CategoryExpense
# from app.smart_recommendation import SmartBudgetRecommender

# app = FastAPI(title="Smart Budget Recommendation API", version="1.0.0")

# # CORS middleware
# app.add_middleware(
#     CORSMiddleware,
#     allow_origins=["*"],
#     allow_credentials=True,
#     allow_methods=["*"],
#     allow_headers=["*"],
# )

# # MongoDB connection - Get from environment variable (set as secret in Hugging Face)
# MONGODB_URI = os.getenv("MONGODB_URI")
# if not MONGODB_URI:
#     raise ValueError("MONGODB_URI environment variable is required. Please set it in Hugging Face secrets.")

# try:
#     client = MongoClient(MONGODB_URI)
#     db = client.expense
#     # Test connection
#     client.admin.command('ping')
#     print("Successfully connected to MongoDB")
# except ConnectionFailure as e:
#     print(f"Failed to connect to MongoDB: {e}")
#     raise

# # Initialize Smart Budget Recommender
# recommender = SmartBudgetRecommender(db)

# @app.get("/")
# async def root():
#     return {"message": "Smart Budget Recommendation API", "status": "running"}

# @app.get("/health")
# async def health_check():
#     try:
#         client.admin.command('ping')
#         return {"status": "healthy", "database": "connected"}
#     except Exception as e:
#         return {"status": "unhealthy", "error": str(e)}

# @app.post("/expenses", response_model=dict)
# async def create_expense(expense: Expense):
#     """
#     Disabled: this service does not create expenses.

#     All expenses should be created by the main WalletSync app and stored
#     directly in MongoDB. This API only reads existing data for analytics.
#     """
#     raise HTTPException(
#         status_code=405,
#         detail="Creating expenses is disabled. Use the main WalletSync app to add expenses.",
#     )

# @app.get("/expenses", response_model=List[Expense])
# async def get_expenses(user_id: str, limit: int = 100):
#     """Get expenses for a user"""
#     expenses = list(db.expenses.find({"user_id": user_id}).sort("date", -1).limit(limit))
#     for expense in expenses:
#         expense["id"] = str(expense["_id"])
#         del expense["_id"]
#     return expenses

# @app.post("/budgets", response_model=dict)
# async def create_budget(budget: Budget):
#     """
#     Disabled: this service does not create budgets.

#     All budgets should be created by the main WalletSync app and stored
#     directly in MongoDB. This API only reads existing data for analytics.
#     """
#     raise HTTPException(
#         status_code=405,
#         detail="Creating budgets is disabled. Use the main WalletSync app to add budgets.",
#     )

# @app.get("/budgets", response_model=List[Budget])
# async def get_budgets(user_id: str):
#     """Get budgets for a user"""
#     budgets = list(db.budgets.find({"user_id": user_id}))
#     for budget in budgets:
#         budget["id"] = str(budget["_id"])
#         del budget["_id"]
#     return budgets

# @app.get("/recommendations/{user_id}", response_model=List[BudgetRecommendation])
# async def get_budget_recommendations(user_id: str, month: Optional[int] = None, year: Optional[int] = None):
#     """
#     Get smart budget recommendations for a user based on past spending behavior.
    
#     Example response:
#     {
#         "category": "Groceries",
#         "average_expense": 3800,
#         "recommended_budget": 4000,
#         "reason": "Your average monthly grocery expense is Rs.3,800. We suggest setting your budget to Rs.4,000 for next month."
#     }
#     """
#     if not month or not year:
#         # Default to next month
#         next_month = datetime.now().replace(day=1) + timedelta(days=32)
#         month = next_month.month
#         year = next_month.year
    
#     recommendations = recommender.get_recommendations(user_id, month, year)
#     return recommendations

# @app.get("/category-expenses/{user_id}", response_model=List[CategoryExpense])
# async def get_category_expenses(user_id: str, months: int = 3):
#     """Get average expenses by category for the past N months"""
#     category_expenses = recommender.get_category_averages(user_id, months)
#     return category_expenses

# if __name__ == "__main__":
#     import uvicorn
#     uvicorn.run(app, host="0.0.0.0", port=8000)